从茶叶提取咖啡因实验方法的改进与探究

Improvement and exploration on the experimental method of extracting caffeine from tea

目的对传统教学实验进行改进，并探究浸泡、煮沸两种不同预处理对茶叶中咖啡因提取率的影响。方法以碧螺春为例，采用超声提取法提取茶叶中咖啡因，并对不同的预处理下咖啡因提取率进行探究并进行统计学分析验证。结果采用煮沸的方式进行预处理的实验组咖啡因平均提取率为0．276％，浸泡的方式进行预处理的对照组咖啡因平均提取率为0．053％，实验组咖啡因粗品提取量明显高于对照组（P〈0．05）。结论改进后的实验相对传统教学实验可以节省1．0～1．5h，克服了传统教学中实验时间过长的问题，可以在正常学时内开展，让学生更好地掌握生物碱的一般提取方法。

Objective This study aims to investigate the influence on the caffeine extraction rate from tea by using two different pre-treatment methods （soaking and boiling）, in order to improve the traditional instruction experiment. Methods The study was choosing the tea named ＂Biluochun＂ as a case study. The caffeine was extracted by using the ultrasonic extraction method. The different caffeine extraction rates from two different pre-treatment methods were collected; hence, the statistical analysis and verification was conducted. Results the average extraction rate from the boiling pre-treatment method （the experimental group） was 0.276 % ; and the average extraction rate from the soaking pre-treatment method （the control group） was 0.053 %.The result has shown that the average extraction rate from the experimental group is higher than the control group （P〈0.05）. Conclusions The improved instruction experiment by choosing an efficient pre-treatment method enable to save 1-1.5 hours. This study overcomes the time- consuming problem during the normal experimental class. In the end, students can better understand the general alkaloid extraction method in a limited class hours.